It has been well known to enlarge the particle size of silver halide particles in a silver halide emulsion in order to increase the sensitivity of the silver halide particle-containing emulsion. However, fog is apt to become significant or the granularity of the silver halide particles often becomes worse with the increment of the particle size of the silver halide particles.
Tabular silver halide particle-containing emulsions are better than other emulsions containing silver halide particles of other shapes with respect to the ratio of sensitivity/granularity, as described in Japanese Patent Application (OPI) No. 58-113926 (the term "OPI" as used herein refers to "unexamined published patent application"). However, when, in order to further increase the sensitivity of the tabular particle-containing emulsion, the particle size of such tabular particles is enlarged, the granularity of the particles becomes worse. It is therefore extremely important to develop a novel method for improving the sensitivity of tabular silver halide particle-containing emulsions without changing the particle size of the silver halide particles and without deteriorating the granularity thereof.